1. Field of the Invention
The present invention relates to a snap-in grommet for a valve stem assembly tire pressure monitoring system.
2. Background Art
Conventional tire pressure monitoring (TPM) systems for vehicles include a tire pressure sensor that is attached to a rim of a vehicle wheel assembly. In some TPM systems, the tire pressure sensor is contained in a sensor housing that includes an air pressure sensor. The sensor senses the air pressure in a tire of the wheel assembly and transmits a signal to a receiver outside the tire. The sensor housing contains a recess. A nut is positioned inside the recess and is threadably connected to a tire valve stem assembly. The valve stem extends through a tire inflator hole in the wheel rim. The sensor housing and nut provide alignment of the sensor, housing and valve stem.
In other conventional TPM systems, the tire valve assembly is inserted through the outside of the wheel rim into the tire pressure monitoring system. In any case, a portion of the tire valve stem protrudes through the tire inflator hole in the wheel rim to provide for inflation and deflation of the tire.
However, insertion of the valve stem into the tire pressure monitoring system through the outside of the wheel rim can lead to difficulties when trying to align the valve stem with the sensor housing of the tire pressure monitor. Furthermore, abrasions are possible when tightening the valve stem assemblies due to the metal-to-rubber contact between the valve stem and the interior of the conventional tire inflator hole grommet and the outer surface of the grommet and the inflation hole. Further still, electrolytic corrosion can occur since the valve stem and the wheel rim are typically implemented using dissimilar metals.
In addition, in conventional approaches to TPM systems, tire valve assembly air leakage from the tire inflator hole can occur. Some conventional tire pressure monitoring devices use a circumferential line element seal and a tapered seal with a flat-faced flange. Sealing is achieved by compressing the circumferential line element seal against the tire inflator hole and compressing the flange seal against the metal valve stem. However, air leakage can still occur from the tire inflator hole when such conventional approaches are utilized. In particular, over-tightening of a valve stem retaining nut can crush and damage one or more sealing regions and cause air leakage.
Thus, there exists a need and an opportunity for a system and a method to improve TPM valve assemblies. Specifically, such an improved system and method may provide improved sealing at interfaces between components of the TPM valve assembly, and may reduce or eliminate abrasion between components of the TPM valve assembly to further improve sealing.